Apparatus for producing sheet glass



Dec.` 13, 1938. J, DRAKE .2,140,281

APPARARATUS FOR PRODUCING SHEET GLASS Filed May 24, 1934 Bnventor czbH/vL. DPM/e'.

Bg f wk Gttomeg Patented Dec. 13, 1938 UNITED STATES PATENT OFFICEbey-Owens-Ford Glass Company,

Toledo,

Ohio, a. corporation of Ohio Application May 24, 1934, Serial No.727,316"

6 Claims.

VThe present invention relates to improvements in apparatus forproducing sheet glass.

While this invention is not limited to use in connection with anyparticular system of manufacturing sheet glass, it is of utility whenassociated with a machine for drawing a continuous sheet of glassupwardly from the surface ofa molten bath and carrying it verticallythrough an annealing leer. The principle of the invention may also beapplied in the so-called Colburn system for producing sheet glass,wherein the sheet, while still in a semi-plastic condition, is deflectedfrom the vertical into the horizontal plane and passed horizontallythrough an annealing leer.

An important object of the invention resides in the provision ofapparatus whereby the formation of surface defects or irregularities inthe sheet being drawn will be reduced to a minimum so that a flatter,smoother and more uniform thickness of sheet may be produced.

' Another object of the invention is the provision of apparatusincluding means engaging the glass sheet while still in a semi-plasticcondition to subject the same to a wiping or smoothing action to flattenor iron out any surface irregularities therein.

A further object of the invention resides in the provision of apparatusembodying a pair of movable wiping surfaces, preferably in the form ofcontinuously revolving rolls, positioned to engage opposite surfaces ofthe sheet to effect such a wiping or smoothing action, said rolls beingarranged in different horizontal planes and also serving to anchor thebase of the sheet and thereby prevent wavering or movement of the lineof generation of the said sheet over the surface ofthe bath of moltenglass from which the sheet is drawn.

Other objects and advantages of the invention will become more apparentduring the course of the following description when taken in connectionwith the accompanying drawing,

In the drawing wherein like numeralsare employed to designate like partsthroughout the same,

Fig. 1 is a vertical longitudinal section through sheet glass apparatusembodying the present invention,

Fig. 2 is a side elevation thereof, partially in section, and Y Fig. 3is a side elevation of a portion of the apparatus showing particularlythe means for driving the wiping orsmoothing rolls.

Referring now to the drawing, thenumeral 5 designates the forward orworking end of a glass melting furnace 6 containing amass of moltenglass 1. Extending transversely within the furnace and dependingdownwardly from the roof 8 thereof are the spaced vertical walls 9 andI0 which dene .therebetween a drawing chamber I I, said chamber beingclosed at each end by an 'end wall I2. That portion of the furnacedisposed beneath the drawing chamber I I is ordinarily termed thedrawingor working area or zone, and drawn upwardly from the surface of theglass within said area or zone, at a point intermediate the verticalwalls 9 and I0, is the glass sheet I3 connected with the mass of glass'I by the meniscus I4. The glass sheet, as it leaves the drawing chamberIl, passes upwardly through a vertical annealing leer I5 of the desiredheight, being carried therethrough between a plurality of pairs of rollsI6 and I1 engaging opposite surfaces of the sheet and which rolls alsoprovide the necessary traction for drawing the sheet upwardly from themolten bath.

One of the leer rolls of each pair, and as here shown the roll I6, ismounted in a relatively xed position while the roll I'I is movabletoward and awayl from roll I6. The means for mounting and driving theserolls is illustrated in Fig. 2 in which I8 designates a driven verticalcountershaft provided with a bevel pinion I9 for each roll I6 meshingwith a bevel gear 20 carried at the corresponding end of the shaft 2l ofthe respective roll. The

shaft 2I is provided at its opposite end with a spur gear 22 me'shingwith a similar gear 23 keyed to the shaft 2 4 of roll I'I so that thepositive rota- Vtion of rolls I6 will be transmitted to rolls Ilthroughthe intermeshing gears 22 and 23. The shaft 24 of each leer rollII is carried at each end thereof by a bell crank leverl 25 pivotedintermediate its ends as at 26 and carrying at its outer end acounterweight 21 which serves to yieldably urge the roll II toward thecorresponding roll IIS. In this manner, the leer rolls I1 are pressedyieldably toward rolls I6 so that breakage of the glass is avoided incase the glass is not perfectly flat and true.

To assist in maintaining the sheet I3 to width, a pair of knurledrollers 28 may be positioned to engage opposite sides of the sheet ateach edge thereof, these rollers being ordinarily arranged closelyadjacent the meniscus I4. Disposed above the knurled rollers 28 andextending at opposite sides of the sheet I3 are coolers 29 and 30respectively, each comprising a substantially rectangular metal casingextending transversely of the sheet and being internally cooled by thecirculation of a suitable cooling medium, such as water, therethrough.

The side walls 9 and I8 of the drawing chamber one-piece constructionand have the lower surfaces thereof spaced slightly above the surface ofthe bath of molten glass. These slabs are 'made of one piece so thatthe-under-surfaces thereof adjacent the molten glass will be unbrokenand free from all joints, thereby tending to eliminate what is known inthe art as cold streaks in the glass passing therebeneath and whichwould be very apt to occur were the slabs formed of a plurality ofblocks arranged' side by side. That is to say, the joints or cracksbetween adjacent blocks would have a tendency to cause cold streaks inthe glass which would result in the formation of a sheet having thickand thinY portions.

Arranged inwardly of the slabs 3| and 32 and suitably carried thereby,if desired, are the horizontal metallic channel members 35 and 36respectively positioned relatively close; to the surface of the mass ofmolten glass 1 and adapted to reflect heat downwardly thereupon so as tolevel out the temperature of the surface glass.

Also, if preferred, there can be submerged in the mass of molten glass1, beneath the vertical walls 9 and I0 of the drawing chamber II, thetwo cooling devices or members 31 and 38 respectively, the function ofwhich is to cool and condition the molten glass flowing into the'drawing area or zone. Each cooling device comprises a pair ofsuperimposed pipes 39 and 40 extending transversely of the furnace andbeing arranged in contact with one another and preferably securedtogether at one or a plurality of points by welding or 1n some othersuitable manner. The pipes 39 and 40 of each cooling device arepreferably in communication with one another at one end thereof so thata suitable cooling medium, such as water, can be continuously circulatedtherethrough.

The greater portion of the glass which is drawn upwardly into the sheetI3 is taken from the surface of the mass of molten glass 1, and thegreater portion of the flow of glass through the furnace is a so-calledsurface flow, the lower strata of glass in the tank having relativelyslight movement. In other words, the glass sheet I3 is drawn mainly fromthe relatively thin surface layer or uppermost' strata of glass in theworking or drawing zone. The cooling devices 31 and 38, while submergedin the mass of glass 1, are preferably positioned relatively close tothe surface thereof. That is to say, the cooling devices are disposedbeneath the surface layer or uppermost strata of lglass from which thesheet is drawn so that they will serve to both condition and cool thisglass as it flows tbereover. The cooling devices will serve not only toreduce the temperature of the surface layer of glass to render itsuitable for the drawing operation but will, in addition, also tend toeliminate or reduce to a minimum the formation of lines and otherdefects in the glass.

In accordance with the present invention, there is arranged within thedrawing chamber II, above the sheet coolers 29 and 30, two relativelylarge rotatable rolls 4I and 42 which are adapted to engage oppositesurfaces of the sheet I3 and to have a wiping vor smoothing actionthereupon to flatten or iron out any irregularities therein. These rollsare adapted to have such a wiping or smoothing action upon the surfacesof the sheet without squeezing the sheet or reducing its thickness. Withthe general type of machine described above, it has been the customaryprac-QN4 tice to position the rolls 4I and 42 directly 0ppm site oneanother, but this arrangement has been found generally unsatisfactorysince it is exceedingly diflicult. if not impossible, to so adjust thesaid rolls that they will contact with the sheet across its entire widthwithout squeezing the sheet or effecting an actual reduction in thethickness thereof. This is due to the fact that the glass sheet is notalways of an absolutely uniform thickness/but, on the other hand, isformed with thick andy thin portions. Consequently, if the rolls werearranged sufficiently close together so as to contact with the thinportions of the sheet, they would naturally tend to squeeze the thickerportions, whereas were they adjusted to just contact with the thickerportions, they would then not contact with the thinner portions of thesheet.

The principal aim and object of this invention, therefore, is to soposition the rolls 4I and 42 relative to one another and also relativeto the glass sheet being formed that they will be caused to contact withall portions of the sheet without squeezing or effecting any actualreduction in the thickness thereof. To this end,'the rolls 4I and 42 arenot disposed opposite or in horizontal alignment with one another, butinstead are 'arranged in different horizontal planes as clearlyillustrated in the drawings, the roll 4I engaging one surface of theglass sheet being disposed beneath the roll 42 engaging the oppositesurface of said sheet. The rolls are also preferably positioned so thatthe innermost portions of the peripheries thereof will be disposedslightly in the path of travel of the glass sheet, as a result of whichthey will engage not only the thick portions but likewise the thinportions of the said sheet as it is being drawn. While there may be aslight deflection in the glass sheet from its normal vertical path oftraveldue to this positioning of the rolls, the amount of deflectionwill be so slight as to be hardly noticeable. In fact, an object of theinvention is to maintain the desired contact between the rolls and theglass sheet with the smallest amount of 'deflection necessary.

As the glass sheet 'is drawn upwardly between the rolls 4I and 42, theopposite surfaces thereof will be subjected to a wiping or smoothingaction tending to fiatten or iron out any surface defects orirregularities which may be present in ably mounted at each side of thefurnace'within a supporting member or cradle designated in its entiretyby the numeral 45, said/supporting member being pivotally mountedintermediate its ends upon a horizontal pin 46 and having formed at itsopposite ends the split bearing portions 41 and 48 within which theadjacent ends of the roll shafts 43 and 44 respectively are journaled.The pins 46 are disposed opposite the edges of the glass sheet anddefine a horizontal axis extending transversely of the sheet in thepath'of travel thereof and about which the supporting members 45 areadapted to be swung to move the rolls 4I 4and 42 simultaneously towardor away from the glass sheet.

In order to effect the desired movement of the supporting members 45 andlikewise to maintain the rolls in adjusted position, there areassociated with each supporting member the two set screws 49 and 50threaded through stationary blocks 5l and 52 .respectively and adaptedto engage the split bearing portions 41 and 48. Thus, when it is desiredto move the rolls toward or away from the glass sheet, it is simplynecessary to eifect the proper adjustment of 'the set screws 49 and 5Bto swing the supporting members 45 upon the pivot pins 46 in a clockwiseor counterclockwise direction. f

The means for driving the'rolls 4| and. 42 include the two sprocketwheels 53 and 54 keyed to the roll shafts 43 and 44 respectively andabout which is trained a sprocket chain 5,5, said chain being trainedabout the sprocket wheels in such a manner that the rolls are caused toturn in opposite directions. The sprocket chain can be driven from anysuitable source of power and may also be trained about a gear 56 mountedupon shaft 51Acarried by a bracket 58 suitably secured to the furnace.can be driven either in the samedirection as the movement of the sheetor in the opposite direction.

While there has been described hereinabove and illustrated in thedrawing the employment of rotatable rolls as the wiping members, yetother types of wiping members may also be used. The essential featuresof theinvention consist in the particular manner of positioningthewiping members relative to one another and also relative to the glasssheet and the means for mounting and adjusting the same.

It is to be understood that the form of the invention herewith shownand-described is to be taken as the preferred embodiment of the same,and that various changes in the shape, size and arrangement of parts maybe resorted to Without departing from the spirit of the invention or thescopev of the subjoined claims.

I claim:

1. In sheet glass apparatus, means for drawing a sheet of glass upwardlyfrom a mass of molten glass, a pair of^members positioned to engageopposite surfaces of the sheet as it is being drawn upwardly and whileit is still in a semiplastic condition, said members being arranged indierent horizontal planes and adapted to have a wiping or smoothingaction upon the opposite surfaces of said sheet toilatten or iron outany virregularities therein, and means for mounting Y semi-plasticcondition, said rotatable members being arranged in different horizontaland vertical planes and adapt to produce a wiping or smoothing actionupon the opposite surfaces of said sheet to flatten or iron out anyirregularities therein, supporting members disposed at oppo- As pointedout above, the rolls.

site ends of said rotatable members for, rotatably supporting the same,and means for pivotranged in different horizontal and vertical planesand adapted to produce a wiping or smoothing action upon the oppositesurfaces of said sheet to flatten or iron out any irregularitiestherein,

means 4for driving said rolls, supporting members disposed at Ioppositeends ofthe rolls for rotatably supporting the same, and horizontal pinsupon which said supporting members are pivotally mounted intermediatetheir ends, said glass sheet. I

4. In sheet glass apparatus, means for drawing a sheet of glass upwardlyfrom a mass of molten glass, a pair of rotatable rolls positioned toengage opposite surfaces of the sheet as it is being drawn upwardly andwhile it is still in a semi-plastic condition, said rotatable rollsbeing arranged in differ nt horizontal and vertical planes and adapte toproduce' a wiping or smoothing action upon the opposite surfaces of saidsheet to Iiatten or iron out any irregularities therein, means fordriving the rolls, supporting members vdisposed at opposite ends of theArolls for rotatably supporting the `same,lhori zontal pins upon whichsaid supporting members are rpivotally mounted intermediate their ends,-said pinsA being disposed opposite the edges of the glass sheet, andmeans for swinging said supporting members upon said pinsto move therolls simultaneously toward and away from said sheet.

5. In sheet glass apparatus, means for. drawing a sheet of glassupwardly from a'mass of molten glass, a pair of members positioned toengage opposite surfaces of the sheet as it is being drawn upwardly andwhile it is still in a semiplastic condition, .said members beingarranged in different horizontal planes and adapted to ,have a wiping orsmoothing action upon the op posite surfaces of said sheet to flatten oriron out any irregularitiestherein, and means for pivotally mountingsaid members for movement toward and away from the sheet.

6. In sheet glass apparatus, means for drawing a sheet of glass upwardlyfrom a. mass of molten glass,` a pair of rotatable members positioned'to engage opposite surfaces of the shag; as it is being drawn upwardlyandwhile it is still bers being arranged in different horizontal vandIvertical planes and adapted to produce a wiping. or smoothing actionupon the opposite surposed at opposite ends of said rotatable members for rotatably supporting the same, and means ior pivotally mounting saidsupporting members to effect movement of said rotatable members towardor away from said sheet.

JOHN L. BRAKE.

pins being 4disposed opposite the edges of the in a semi-plasticcondition, said rotatable mem.

faces of said sheet to ilattenlor iron out any irregularities therein,.supporting members dis-

